Leona curiously asked, "Teacher, do the foods we eat really just pass through those winding tubes and turn into energy our body can use?" Teacher Star smiled mysteriously, "It's not just a simple 'pipeline project'! There's a team of super helpers inside our body!"

Teacher Star continued, "These 'super helpers' are our digestive glands, acting like a professional 'chemical decomposition team' inside our bodies! They secrete various special digestive juices, specifically responsible for breaking down large nutrient molecules from food into tiny, easily absorbable units."

"Just like a cooking team, each member has their own special skill!" Teacher Star said, pointing to a diagram of food breakdown. "First, there are the salivary glands. When we put food in our mouth, the saliva they secrete begins the preliminary breakdown of carbohydrates. That's why rice tastes sweeter when you chew it for a while!"

Leona exclaimed, "Wow, so the work starts in the mouth! What's next?" Teacher Star winked, "Next, the food arrives in the stomach. The gastric glands secrete powerful gastric juice, specifically targeting proteins. Imagine it like a chef specializing in 'meat feasts'!"

"There's also a very important helper – the liver!" Teacher Star continued. "Although it doesn't directly break down food, it secretes bile. Bile acts like 'dish soap,' emulsifying large, greasy fats into tiny droplets, making them easier for later digestive juices to process."

Leona nodded, "So fats need special treatment!" Teacher Star added, "Exactly! And the pancreas is an all-rounder. Its pancreatic juice can break down carbohydrates, proteins, and lipids all at once, just like a versatile super chef!"

"Finally, we reach the small intestine!" Teacher Star announced. "Here, the intestinal glands secrete intestinal juice, responsible for completing the final stage of breakdown, ensuring all large molecules are cut into the smallest units the body can directly absorb. Like a pastry chef, putting the perfect finishing touch on this digestive feast!"

Leona pondered, "So many different digestive juices, is it because each nutrient is different?" Teacher Star nodded approvingly, "Precisely! Just like different locks need different keys. Starch requires the cooperation of saliva, pancreatic juice, and intestinal juice to break down into glucose; proteins need gastric juice, pancreatic juice, and intestinal juice to break down into amino acids; and lipids must first be emulsified by bile, then broken down by pancreatic juice into fatty acids and glycerol."

"Once these nutrients become small molecules, they arrive at the main absorption arena – the small intestine!" Teacher Star pointed to an image filled with villi. "The inner wall of the small intestine is covered with brush-like villi, which greatly increases the absorption surface area. These villi can quickly deliver nutrients to all parts of the body, like an efficient distribution center!"

Leona suddenly understood, "So digestion isn't just a journey, it's a precise chemical transformation show! Without the hard work of these digestive glands and juices, no matter how much delicious food we eat, our bodies wouldn't be able to absorb it!"